Key moment

United had been applying the pressure ever since dropping behind, only to be frustrated by Wolfsburg's stubborn back line.

Meanwhile, Mata had been enjoying plenty of space in the opposition box, without managing to find a decisive touch. It wasn't until he picked the ball up on the right of the area in the 34th minute that United finally made their pressure count.

His cross caught the arm of Daniel Caligiuri and referee Victor Kassai immediately pointed to the spot.

Mata duly stepped up and swept the ball home to hand United a vital equaliser before the break.

Good day

Mata's movement caught Wolfsburg's defenders napping time and time again - particularly in the first half. While the Germans concerned themselves with the pace of Martial and Depay, Mata was allowed to drift into pockets of space.

The Spaniard proved to be the difference, winning and scoring a first half penalty - and then providing a deft flick to set up Chris Smalling's goal in the 53rd minute.

Bad day

Antonio Valencia was hooked at half time and you have to wonder whether he has blown his chance to establish himself at right back.

The Ecuadorian had been a doubt for the match due to injury, but that could not excuse his woeful positioning as Caligiuri fired Wolfsburg ahead early on.

Van Gaal craves balance and Valencia does provide that. But with Ashley Young an option on either side in the absence of the injured Luke Shaw and Phil Jones also capable of playing on the right, United' Dutch manager may have a rethink for Sunday's game against Arsenal.

Bigger picture

Victory at home puts United on course to meet Van Gaal's target of three straight wins at Old Trafford.

But this was evidence of just how tough a group they find themselves in.

Wolfsburg will be no pushover in Germany and PSV have already shown what threat they possess after their 2-1 victory against United earlier this month.

Meanwhile, CSKA Moscow's 3-2 win against the Dutch champions should serve as enough of a warning to United ahead of their trip to Russia in the next round of fixtures.